By ANNA USHER

Thieves have stolen a Porsche, a BMW and a Mazda from a Mosman home, breaking in to grab five sets of car keys as the owners slept just metres away.

The pair woke to footsteps and the sound of heavy joggers on the staircase about 1.30am on Friday 7 August. Within 10 minutes, all three cars were gone from the property.

It is the latest hit in a wave of key-grab break-ins sweeping the lower north shore, where thieves slip into family homes just to get their hands on luxury cars.

North Shore Police Area Command told Mosman Collective the white Porsche Cayenne was dumped 20 kilometres away in Campsie, in Sydney’s south-west. The white BMW sedan was found crashed on Military Road shortly after the robbery.

The white Mazda sedan was run to ground after a police pursuit.

One person was arrested after that chase.

A police spokesperson says the investigation is moving fast and more arrests are expected.

The 9pm routine

Detectives are urging every household on the lower north shore to lock up properly before bed and to keep car keys out of sight and away from doors and windows.

They want residents to make a “9pm routine” part of the nightly habit: secure all doors and windows, hide car keys, remove spare keys from vehicles, lock garages and side gates, and switch on alarms and CCTV.

“Many break and enter offences are opportunistic,” police said. A few minutes each night can be the difference between a quiet night and waking up to an empty driveway.

Police say they are committed to apprehending the offenders and putting them before the courts, but they are asking residents to stay alert and report anything suspicious.

Anyone who sees suspect activity is urged to call police. In an emergency, call triple-0. For non-urgent help, the Police Assistance Line is 131 444.